Philip Cowley finds the incumbency factor alive and well in 2010

The first obvious evidence of what (at least to me) was one of the more surprising aspects of the election results came at just past 2am on 7 May, when Labour held Gedling. It was the first obvious manifestation of something which the 10pm exit poll had claimed to detect, but which I wanted to see for myself before I believed it: evidence that hard-working Labour incumbents – in this case, Vernon Coaker – could survive against the swing.

The Conservatives would end the election having taken almost a clean sweep of seats from Labour in their top 100 targets. But of the nine they failed to take, eight were held by an incumbent Labour MP.

In one sense, this should not have been surprising: a growing incumbency factor has been building up over recent elections, as MPs work the constituency increasingly hard. But most observers (and almost every politician I spoke to) had assumed that the expenses scandal would mean that 2010 would be the very worst election to be an incumbent, the best to be a challenger. Yet with many of the ‘worst’ expenses offenders gone, those MPs remaining were still able to reap the benefits of incumbency.

In The British General Election of 2010 John Curtice and colleagues found that the difference was around two percentage points.  Labour’s vote fell by an average of 7.4 percentage points in its seats that were not defended by the incumbent MP, more than two points higher than the equivalent statistic in seats where the incumbent stood again (–5.2).

But here’s the bad news for Labour: incumbency works for Conservatives too.  The Conservative vote rose on average by 2.9 percentage points in Conservative held seats that were not being defended by an incumbent, but 4.1 points where the incumbent MP was still in place. And incumbent Conservative MPs who first won their seats in 2005 – and who thus had the opportunity to acquire a personal vote for the first time – saw their vote increase on average by 5.6 points.

Joan Ryan had a fascinating piece in Progress recently, looking at the seats that Labour lost in 2005 – and where the Labour vote has since slumped.  In six of those seats, Labour is now third.

So the really bad news for Labour is that in 2015 (or whenever) Labour will be facing scores of fresh-faced Conservative MPs who have spent the last five years furiously digging in; you will be trying to capture some of the toughest political terrain ever – seat after seat inhabited by first term incumbents. Be prepared for a tough fight.

Philip Cowley is professor of Parliamentary government at the university of Nottingham and author (with Dennis Kavanagh) of The British General Election of 2010, just published by Palgrave and reviewed in Uncut next week.

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2 Responses to “Philip Cowley finds the incumbency factor alive and well in 2010”

  1. The seats where we came third are not due to incumbency. They’re due to the Labour vote half-holding up in 2005 under protest because, despite Iraq and all the other things that lost those seats for us, we still weren’t Tories.

    In 2010 we didn’t hold the seat, so they voted Lib Dem, as we weren’t offering them anything. Because they’re southern seats that we can win, which, contra Diamond and Radice, have almost nothing to do with the south as a whole.

    None of which is to say that incumbency doesn’t matter. Quite the reverse. Without it we’d have lost those seats much worse in 2010. The number of constituents I met in Cambridge who voted for Anne Campbell in 2005 on personal grounds and couldn’t stomach voting Labour in 2010 must have numbered in the low hundreds by the end of the campaign.

  2. Dave Collins says:


    Are you able to quantify the incumbency factor? The value of personal votes has long been diusputed – candidates swear they are often decisive, agents generally reckon them pretty derisory. Secondly, is there any way of determining how much of the ‘incumbency bonus’ is enjoyed by all incuments vis a vis the additional element ‘earned’ by the MP really slogging her/his guts out doing the casework and the retail politics on the ground?

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